| Ivo (2) | | - | Bulgarian, Serbian, Croatian, Macedonian | |
| Ivona | | - | Czech, Slovak, Croatian, Macedonian | |
| Jadran | | - | Croatian, Serbian, Slovene | |
| Jadranka | | - | Croatian, Serbian, Slovene | |
| Jadranko | | - | Croatian, Serbian, Slovene | |
| Jaga | | - | Croatian, Serbian, Macedonian | |
| Jagoda | | yah-GAW-dah (Polish) | Croatian, Serbian, Macedonian, Polish | |
| JakŠA | | YAHK-shah | Croatian | |
| Jakov | | - | Serbian, Croatian, Macedonian | |
| Jana (2) | | YAH-nah | Croatian, Serbian | |
| Janja | | - | Croatian, Serbian | |
| Janko | | - | Slovene, Croatian, Serbian, Slovak | |
| Jasmina | | - | Croatian, Serbian, Slovene, Macedonian | |
| Jasminka | | - | Croatian | |
| Jasna | | - | Croatian, Serbian, Slovene, Macedonian | |